Clockwork mechanism



June 1951 A. H. SANBORN 2,556,110

, CLOCK WORK MECHANISM Filed July 30, 1945 4 Sheets-Sheet 2 JLI 2.4

June 5, 195] A. H. SANBORN 2,556,

CLOCK WORK MECHANISM Filed July 30, 1945 4 Sheets-Sheet 3 June 5, 1951 A. H. SANBORN 2,556,110

CLOCK WORK MECHANISM 4 Sheets-Sheet 4 Filed July 30, 1945 Patented June 5, 1951 UNITED STATES PATENT OFFICE CLOCKWORK MECHANISM Arthur H. Sanborn, Chicago, Ill.

Application July 30, 1945, Serial No. 607,684

2 Claims. 1

The present invention relates. to clock work mechanism and more particularly echanism for use with electric clocks.

An object of the present invention is to provide improved mechanism for electric clocks.

Another object. of the present, invention is to provide electric clock mechanism in which fewer gears are used.

Another object of the present invention is to provide an electric clock mechanism with the shafts and gears concentrically arranged, thus reducing the cost of manufacture and assembly.

A Still further object of the present invention is to. provide a novel gear train for electric clock mechanism.

The above, other and further objects of the present invention will be apparent from. the following description and accompanying drawings.

An. embodiment of the present invention is illustrated in the accompanying drawings, and the views thereof are as follows:

Figure 1 is. a central sectional view through an electric clock showing the mechanism or the present invention, showing some parts in elevation and other parts in section.

Figure 2 is an elevational view of one pair of gears designed for a sixty to, one reduction and illustrating one manner of limiting the spur gear to gyratory movement.

Figure 3 is a similar view showing a gear reduction of twelve to one.

Figure 4 is a view of a pair of gears arranged for a twelve to one reduction and showing a different means for constraining the spur gear to gyratory movement.

Figure 5 is a fragmented View of teeth of a pair of gears showing the relative position of the same for a portion of travel of the gears.

The drawings will now be explained.

Referring to Figure 1, av casing iii of suitable construction is provided with a transparent crystal of glass or other suitable material, designated at I Within the casing is a clock frame designated generally at A, which includes parallel plates 12 and I3 suitably secured in spaced relation and maintained in spaced relation by suitable separators E4. on the outer surface of the plate 52 is a clock dial, not. shown, as is customary.

Attached to the rear plate i3 is a motor !5, the motor being attached in any suitable manner as for example by bolts or rivets through spacers The motor has a projecting shaft ll which enters through a suitably disposed aperture l8 in the rear plate l3, the shaft projecting into the space between the plates 12 and I3. An eccentric l9 is secured to or formed as a part of the motor shaft ll.

A second hand shaft Zil has its inner end bored at 2! to receive and provide a guide for the projecting end of the motor shaft H. The minute hand shaft 22 is formed as a sleeve surrounding a portion of the second hand shaft. The hour hand shaft 23 is also formed as a sleeve and sur rounds a, portion of the minute hand shaft. 22.

In transmitting motion to the several shafts reduction gear mechanism is. employed.

The arrangement in Figure 1 shows the. parts necessary for proper gear reduction with a motor having a speed of R. P. M. For effecting the necessary gear reduction a plurality of pairs of gears. are utilized, there being three such pairs shown in Figure 1, and identified as. B, C and D, with the pair B nearest the motor IS.

The pair B has a spur gear 24 gyrated bythe eccentric [9 of the motor shaft ll. There are 59 teeth in. this gear. A ring gear 25 i keyed to the second hand shaft 2! and has its margin formed as an internal gear, with the teeth thereof in the plane. of the spur gear 24, There are 60 teeth in the ring gear 25.

The second hand shaft 20. is provided with an eccentric 26 which carries the spur gear 21 of the pair C. The ring gear 28. of the pair C is frictionally secured to the minute hand shaft 22.

The minute hand shaft 22 is provided with an eccentric 29 which carries the spur gear 30 of the pair D. The ring gear 3! of the pair D is keyed to the hour hand shaft 23.

There are 59 teeth on the spur gear 2,! of, the pair C, and 55 teeth on the spur gear 30 of the p ir D. All of he. rin ears have 60 teethin order that the. clock may he set, manually, a spur gear 32 is keyed to. the minute hand shaft 2. A pinion 33 meshes with the spur gear 32 and is provided with a stem 34 having a knurled nut 35 on its outer end, outwardly of the casing [0, so as to be easily operable to set the clock.

The frictional mounting of the ring gear 28 of the pair 0 is illustrated as having the central portion of the gear in bodily contact with the spur gear 32. Between the other face of the body of the ring gear and a shoulder 26 formed in the second hand shaft 26 is a washer 31 of conventional star formation. The washer bears against the ring gear 28 to frictionally connect the ring gear 28 to the minute hand shaft 22 in driving relation. The frictional mounting of the ring gear 28 is such that when the nut 35 is manipulated to set the clock, the minute hand shaft may be rotated with safety to the mechanism.

A second hand 38 is secured to the second hand shaft 20, a minute hand 39 is secured to the minute hand shaft 22, and an hour hand 40 is secured to the hour hand shaft 23 to be swept over the dial in the customary manner.

For limiting the spur gears 24, 27 and 30 to gyratory movement, a plurality of spring fingers are utilized.

There are four such fingers per gear quadrangularly arranged and connected to the spurs.

Referring to Figures 1, 2, and 3, the spring fingers are illustrated as wires having similar ends mounted in sockets 4| suitably fastened to a fixed face, such as a Wall of the casing. The wires are held in place in the sockets by means of set screws 42. A wire 43 projects outwardly from its fixed support and is bent to extend along a portion of the surface of its spur gear. Its outer end 44 is bent at right angles to its length and entered in anaperture 45 in the spur gear 24. Other wires 4B, 4? and 48 are similarly connected to the spur gear 24. These four wire fingers, per gear, permit gyratory motion of the spur without allowing any rotative motion. Figures 2 and 3 illustrate in full and dotted lines the bending of certain portions of the wires as the spur gear is driven.

The wire fingers for the other spur gears are of similar nature, similar arrangement and connection, and function in the same manner as described with reference to the spur gear B.

Figure 4 illustrates other means for confining l a spur gear to gyratory movement.

' In this figure the ring gear is designated at 49, the spur gear 50 and the cam 5|. An X member E has a hub portion 52 with a central aperture 53, the perimeter of which is greater than the orbit of the high point of the cam 5|. Two oppositely extending arms 54 and 55 are constrained to straight line movement. Shown in this figure the outer ends of the arms 54 and 55 are formed with open ended slots 56 and 51 respectively, receive fixed bars 58 and 59, which are suitably secured in the clock framework. The bars 58 and 59 could be the spacers [4, moved toward the axis of the frame, to serve the dual purpose of connecting the plates I2 and I3 and also guiding the members E of the various pairs of gears.

Two other arms, 60 and BI, arranged at right angles to the arms 54 and 55, and extending outwardly from the housing 52 of the member E are provided with elongated slots 62 and 63. Secured to the face of the spur gear 50, by rivets G3 or the like, are elongated blocks 64 and 65 which blocks enter the slots 62 and 63 respectively of the arms 60 and GI. The slots are arranged with their lengths in the direction of the lengths of the arms. The lengths of the blocks 84 and 55 are less than the lengths of the slots. The construction is such that as the cam 5: is driven the arms 54 and 55 move in straight line direction and the blocks 64 and 65 work back and forth in the arm slots to confine the spur gear 50 to gyratory movement.

In Figure 4 there is shown in full lines, near the bottom of the figure, tooth engagement between the spur 5D and the ring gear 49 when the high point of the cam 5! is at six oclock, in dotted lines, at nine oclock is shown engagement of some of the spur teeth with some of the ring gear teeth, illustrating the manner of travel of the spur gear in its gyratory path.

As before stated, the mechanism is shown in connection with a motor making 60 R. P. M. With such arrangement there is a 60 to 1 reduction between the motor shaft and the second hand shaft. There is a 60 to 1 reduction between the second hand shaft and the minute hand shaft, and a 12 to 1 reduction between the minute hand shaft and the hour hand shaft.

In the event a motor is utilized making 1200 R. P. M., then two reductions would be made between it and the second hand shaft, one a 20 to 1 reduction and the next a 60 to 1 reduction, the first being accomplished by utilizing a spur gear having 57 teeth working With a ring gear having 60 teeth and a second reduction achieved by a spur gear having 59 teeth working with a ring gear having 60 teeth.

' In the event a 1200 R. P. M. motor is used, the additional reduction means would be the same as those herein described, namely pairs of gears similar to pairs B, C and D.

Inasmuch as the spring fingers 43 are the same for all of the pairs of gears, all of the fingers will be given similar reference characters.

It will be observed that by means of the present invention an electric clock mechanism may be made with the shafts and the gears all concentrically arranged, with some of the shafts as sleeves. This construction reduces cost of manufacture and assembly and lends itself very readily to ease of maintenance and repair.

No means have been shown for preventing relative endwise movement of the shafts, as such means are well understood in the clock making art, inasmuch as the drawing in Figure 1 is somewhat diagrammatic in character.

The second hand shaft will sometimes herein be referred to as the second shaft, the minute hand shaft will be referred to as the third shaft, and the hour hand shaft will be referred to as the fourth shaft.

The pair of gears B will sometimes be referred to as the first pair, the pair C will be referred to as the second pair, and the pair D as the third pair.

The teeth of the internal gears must be formed with the dedendum portions only, while the teeth of the spur gears may be formed with addendum ortions only.

It will be apparent that a clock mechanism constructed in accordance with the present invention is one in which the element of friction is reduced to a minimum thus prolonging the life of such mechanism and assuring accuracy of operation for a long period of time.

While no means are shown for access to the interior of the case 10, any suitable means may be utilized, as is well understood in the art.

The teeth of the pairs of gears are shaped to provide a pressure angle greater than the usual angle of 14 The invention has been described herein more or less precisely as to details, yet it is to be understood that the invention is not to be limited thereby, as changes may be made in the ar rangement and proportion of parts, and equivalents may be substituted, without departing from the spirit and scope of the invention.

The invention is claimed as follows:

1. A clockwork mechanism comprising a synchronous motor, a motor shaft protruding therefrom, a second hand shaft bored at one end to receive the motor shaft, 2. minute hand shaft formed as a sleeve surrounding a portion of the second hand shaft, an hour hand shaft formed 5 as a sleeve surrounding a portion of the minute hand shaft, all of said shafts having a single common axis, reduction gear mechanisms for transmitting motion from the motor shaft to the several hand shafts, each of said mechanisms ineluding a spur gear having teeth with addendum portions only and a cooperating internal ring gear having teeth with dedendum portions only, said'mechanisms further including eccentrics on the shafts to gyrate the spur gears, and means associated with the spur gears to constrain the spur gears to gyratory motion only.

i 2. A clockwork mechanism for an electric clock comprising a synchronous motor, sweeptype clock hands for indicating hours, minutes and seconds, shaft means between the motor and the clock bands including a motor shaft, a second hand shaft connected thereto, and sleevetype minute and hour shafts, and three airs of cooperating ring and spur reduction gears to 20 6 and means to constrain the movement of the spur gears to a gyratory path.

ARTHUR H. SANBORN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 244,663 Powell July 19, 1881 1,365,492 Haltee Nov. 11, 1921 1,590,156 Howard June 22, 1926 1,615,664 Warren Jan. 25, 1927 2,058,609 Magro Oct. 27, 1936 2,303,365 Karlsen Dec. 1, 1942 FOREIGN PATENTS Number Country Date 44,954 France Feb. 4, 1935 (1st addition) 368,643 Germany Feb. 9, 1923 439,035 Great Britain Nov. 28, 1935 

